Thermal transfer sheet and combination of transfer foil and thermal transfer sheet

ABSTRACT

The present invention provides a thermal transfer sheet that can accurately remove a transfer layer, and a combination of a transfer foil and the thermal transfer sheet. A thermal transfer sheet  10  comprising a peel-off layer  4  on a substrate  1 , wherein the peel-off layer  4  (i) contains at least a vinyl chloride-type resin and an acrylic-type resin, and a mass of the vinyl chloride-type resin based on a total mass of the peel-off layer  4  is more than 50% by mass and not more than 95% by mass, or the peel-off layer  4  (ii) contains a polyester-type resin having a number average molecular weight (Mn) of not more than 17000, and having a glass transition temperature (Tg) of not less than 50° C. and not more than 120° C.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.16/082,366, filed Sep. 5, 2018, which in turn is the National Stageentry of International Application No. PCT/JP2017/009043, filed Mar. 7,2017, the entireties of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a thermal transfer sheet, and acombination of a transfer foil and a thermal transfer sheet.

BACKGROUND OF THE INVENTION

As proposed in Patent Literature 1, an intermediate transfer medium inwhich a transfer layer including a receiving layer (which may bereferred to as a transfer layer, hereinafter) is peelably provided on asubstrate is used as a device for forming a print without havingconstraints on the types of transfer receiving articles. With thisintermediate transfer medium, a print in which a thermal transfer imageis formed on any transfer receiving article can be obtained by using athermal transfer sheet having a colorant layer to form a thermaltransfer image on the receiving layer of the intermediate transfermedium, and then transferring the transfer layer including the receivinglayer onto any transfer receiving article. In particular, theintermediate transfer medium is particularly preferably used for, forexample, a transfer receiving article on which a colorant is less likelyto be transferred, and a high-quality image cannot be directly formed,or a transfer receiving article that is likely to fuse with the colorantlayer during thermal transfer.

Depending on the types of prints obtained by transferring the transferlayer of the intermediate transfer medium onto a transfer receivingarticle, it may be necessary to leave a certain region, for example, aregion allocated for an IC chip, a magnetic stripe, a transmitting andreceiving antenna unit, a signature portion, or the like. Thus, on thesurface of the transfer receiving article, there may be regions thatcause inconvenience if they are covered with the transfer layer. Inother words, there are some cases where the surface of the transferreceiving article needs to be exposed.

Under these circumstances, an attempt has been made to use a thermaltransfer sheet in which a peel-off layer is provided on one surface of asubstrate, to remove (which may also be referred to as peel off), inadvance of transferring a transfer layer of an intermediate transfermedium onto a transfer receiving article, a predetermined region of thetransfer layer, such as a region of the transfer layer where transferonto the transfer receiving article is not intended, by means of thepeel-off layer. For example, Patent Literature 2 proposes a method andthe like in which a peel-off layer of a thermal transfer sheet and atransfer layer of an intermediate transfer medium are superposed on eachother to contact each other, and then energy is applied to the othersurface of the substrate of the thermal transfer sheet to remove apredetermined region of the transfer layer corresponding to the regionto which energy has been applied, by means of the peel-off layer.

The above-described thermal transfer sheet having the peel-off layer isrequired to have the function of accurately removing a predeterminedregion of the transfer layer, in other words, is required to have thefunction of removing a predetermined region of the transfer layer, asintended. In fact, however, a portion of the transfer layer that shouldbe removed with the peel-off layer often remains on the intermediatetransfer medium, and there is room left for improvement in this respect.

CITATION LIST Patent Document Patent Literature 1: Japanese PatentLaid-Open No. 2014-80016 Patent Literature 2: Japanese Patent Laid-OpenNo. 2003-326865 SUMMARY OF THE INVENTION Technical Problem

The present invention has been made in view of the above-mentionedcircumstances, and principally aims to provide a thermal transfer sheetthat can accurately remove a predetermined region of a transfer layer,and a combination of a transfer foil and the thermal transfer sheet.

Solution to Problem

A thermal transfer sheet according to an embodiment of the presentdisclosure for solving the above-mentioned problem is a thermal transfersheet comprising a peel-off layer on a substrate, wherein the peel-offlayer contains at least a vinyl chloride-type resin and an acrylic-typeresin, and a mass of the vinyl chloride-type resin based on a total massof the peel-off layer is more than 50% by mass and not more than 95% bymass.

Furthermore, a thermal transfer sheet according to an embodiment of thepresent disclosure for solving the above-mentioned problem is a thermaltransfer sheet comprising a peel-off layer on a substrate, wherein thepeel-off layer contains a polyester-type resin having a number averagemolecular weight (Mn) of not more than 17000, and having a glasstransition temperature (Tg) of not less than 50° C. and not more than120° C.

The polyester-type resin may be a polyester-type resin having a numberaverage molecular weight (Mn) of not less than 3500 and less than 9000.The polyester-type resin may also be a polyester-type resin having aglass transition temperature (Tg) of not less than 50° C. and not morethan 100° C.

Furthermore, a combination according to an embodiment of the presentdisclosure for solving the above-mentioned problem is a combination of atransfer foil and a thermal transfer sheet, wherein the transfer foilhas a structure in which a transfer layer is provided on a support suchthat the transfer layer can be peeled off from the support, the thermaltransfer sheet has a structure in which a peel-off layer is provided ona substrate, and under conditions in which the transfer foil and thethermal transfer sheet are superposed on each other such that thetransfer layer and the peel-off layer are opposed to each other, and atransport speed for the thermal transfer sheet is set to 42.3 mm/sec,and energy applied to the thermal transfer sheet is set to 0.143 mJ/dot,adhesion between the transfer layer and the peel-off layer as measuredwhen a predetermined region of the transfer layer is removed by means ofthe peel-off layer is not less than 0.03 N/cm.

The adhesion as measured when the energy applied to the thermal transfersheet is changed in the range of not less than 0.1 mJ/dot and not morethan 0.2 mJ/dot may be not less than 0.03 N/cm.

Advantageous Effects

With the thermal transfer sheet of the present invention or thecombination of a transfer foil and a thermal transfer sheet of thepresent invention, a predetermined region of the transfer layer can beaccurately removed by means of the peel-off layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view of a thermal transfer sheetaccording to an embodiment.

FIG. 2 is a schematic cross-sectional view showing a state in whichenergy is applied to a combination of the thermal transfer sheetaccording to an embodiment and an intermediate transfer medium.

FIG. 3 is a schematic cross-sectional view showing a state in whichenergy is applied to a combination of a comparative thermal transfersheet and an intermediate transfer medium.

FIG. 4 is a schematic cross-sectional view of the thermal transfer sheetaccording to an embodiment.

FIG. 5 is a schematic plan view of an intermediate transfer medium foruse in combination with the thermal transfer sheet according to anembodiment.

FIG. 6 is a schematic diagram showing one example of a printer for usein removing the transfer layer by means of the peel-off layer of thethermal transfer sheet according to an embodiment.

DETAILED DESCRIPTION OF THE INVENTION <<Thermal Transfer Sheet>>

A thermal transfer sheet 10 according to an embodiment of the presentdisclosure (hereinafter referred to as the thermal transfer sheetaccording to an embodiment) has a structure in which a peel-off layer 4is provided on one surface of a substrate 1, as shown in FIG. 1. In theembodiment shown in FIG. 1, a back face layer 5 is provided on the othersurface of the substrate 1, and a primer layer 2 is provided between thesubstrate 1 and the peel-off layer 4. The primer layer 2 and the backface layer 5 are optional constituents in the thermal transfer sheetaccording to an embodiment.

The thermal transfer sheet 10 according to an embodiment is a thermaltransfer sheet used for removing a predetermined region of a transferlayer of an intermediate transfer medium. Specifically, as shown in FIG.2, the thermal transfer sheet 10 is used for the following purpose: thepeel-off layer 4 of the thermal transfer sheet 10 and a transfer layer31 of an intermediate transfer medium 30 are superposed on each other,energy is applied to the back surface side of the thermal transfer sheet10 by means of a heating device 16 such as a thermal head, and apredetermined region of the transfer layer 31 of the intermediatetransfer medium 30 corresponding to the region to which energy has beenapplied is removed. Hereinafter, the present invention will be describedreferring to a case where the transfer layer to be removed by thepeel-off layer 4 of the thermal transfer sheet 10 according to anembodiment is the transfer layer of the intermediate transfer medium.However, the transfer layer to be removed by the peel-off layer 4 of thethermal transfer sheet 10 according to an embodiment may also be atransfer layer of a protective layer transfer sheet. The transfer layerof the intermediate transfer medium has a single-layer structurecomposed of a receiving layer only, or a layered structure in which areceiving layer and other layers are layered. The transfer layer of theintermediate transfer medium is provided on a support such that it canbe peeled off from the support. When the transfer layer of theintermediate transfer medium has a layered structure composed of notless than two layers, the receiving layer is positioned farthest fromthe support. The transfer layer of the protective layer transfer sheethas a single-layer structure composed of a protective layer only, or alayered structure in which a protective layer and other layers arelayered. The transfer layer of the protective layer transfer sheet isprovided on a support such that it can be peeled off from the support.Examples of other layers include a release layer. The transfer layer ofthe intermediate transfer medium or the transfer layer of the protectivelayer transfer sheet after being peeled off from the support istransferable onto a transfer receiving article. An object having atransfer layer other than the above may also be used. The removalperformance for removing a predetermined region of the transfer layer 31of the intermediate transfer medium 30 by using the thermal transfersheet 10 having the peel-off layer 4 will be hereinafter called the“peel-off property”. Herein, “good peel-off property” means that apredetermined region of the transfer layer can be accurately removed bythe peel-off layer 4, in other words, the transfer layer 31 can beremoved as intended. As used herein, “thermal transfer sheet” is acollective term for media to which a heating device such as a thermalhead is applied. “Thermal transfer sheet” also includes a thermaltransfer sheet that is used for removing a portion of the transfer layer31 of the intermediate transfer medium 30 by applying a heating device,and has a structure in which the peel-off layer 4 is provided on onesurface of the substrate, as in the present invention.

(Substrate)

There is no limitation on the substrate 1 forming the thermal transfersheet 10 according to an embodiment, and a substrate selected asappropriate from those known in the field of thermal transfer sheets canbe used. Examples of the substrate include thin paper such as glassinepaper, condenser paper, and paraffin paper; and stretched or unstretchedplastic films, for example, polyesters having high heat resistance suchas polyethylene terephthalate, polyethylene naphthalate, polybutyleneterephthalate, polyphenylene sulfide, polyether ketone, and polyethersulfone, polypropylene, polycarbonate, cellulose acetate, polyethylenederivatives, polyvinyl chloride, polyvinylidene chloride, polystyrene,polyamide, polyimide, polymethylpentene, and ionomers. Composite filmsobtained by layering two or more of these materials can be also used.

While there is no particular limitation on the thickness of thesubstrate 1, the thickness is preferably not less than 2 μm and not morethan 10 μm. Furthermore, the surfaces of the substrate 1 may besubjected to an adhesive treatment to improve the adhesion between thesubstrate 1 and the below-described peel-off layer 4. That is, theadhesive-treated substrate 1 may be used. Examples of the adhesivetreatment include known resin surface-modifying techniques, such as acorona discharge treatment, a flame treatment, an ozonization treatment,an ultraviolet treatment, a radiation treatment, a surface rougheningtreatment, a chemical treatment, a plasma treatment, a low-temperatureplasma treatment, and a grafting treatment. These treatments may be usedin a combination of two or more. Instead of using the adhesive-treatedsubstrate 1, or together with the adhesive-treated substrate 1, thebelow-described primer layer 2 may be provided between the substrate 1and the peel-off layer 4.

Peel-Off Layer According to a First Embodiment

As shown in FIG. 2, the peel-off layer 4 forming the thermal transfersheet 10 according to an embodiment is a layer that serves to remove apredetermined region (region where removal is intended) of the transferlayer 31 of the intermediate transfer medium 30. Specifically, thepeel-off layer 4 is a layer used for the following purpose: the transferlayer 31 of the intermediate transfer medium 30 and the peel-off layer 4of the thermal transfer sheet 10 are superposed on each other, energy isapplied to the back surface side of the thermal transfer sheet 10 bymeans of the heating device 16 such as a thermal head, and the transferlayer 31 positioned in a region corresponding to the region to whichenergy has been applied is removed. The intermediate transfer medium 30according to the embodiments shown in FIGS. 2 and 3 has a structure inwhich the transfer layer 31 is provided on the support.

Herein, in the thermal transfer sheet 10 according to an embodiment, thepeel-off layer 4 contains a vinyl chloride-type resin and anacrylic-type resin, and a mass of the vinyl chloride-type resin based ona total mass of the peel-off layer 4 is more than 50% by mass and notmore than 95% by mass. The peel-off layer having these features may behereinafter referred to as the peel-off layer according to the firstembodiment.

With the thermal transfer sheet 10 according to an embodiment having thepeel-off layer according to the first embodiment, a predetermined regionof the transfer layer 31 where removal is intended can be accuratelyremoved by the peel-off layer 4 according to the first embodiment.

Even if the peel-off layer 4 contains a vinyl chloride-type resin and anacrylic-type resin, a sufficiently satisfactory peel-off property cannotbe obtained if the mass of the vinyl chloride-type resin based on thetotal mass of the peel-off layer 4 is not more than 50% by mass.Specifically, the transfer layer positioned near the boundary between anon-removal region and a removal region of the transfer layer whereremoval by the peel-off layer is intended cannot be accurately removed,and a portion of the removal region of the transfer layer that should beoriginally removed is likely to remain on the intermediate transfermedium. As a result, a predetermined region of the transfer layer 31where removal is intended cannot be accurately removed. Alternatively,with the boundary between a removal region and a non-removal region as astart point, a portion of the transfer layer in the non-removal regionis removed in such a manner as to trail the transfer layer in thenon-removal region, and the transfer layer that should originally remainon the intermediate transfer medium, that is, the transfer layer in thenon-removal region, is removed along with the transfer layercorresponding to the removal region. As a result, a predetermined regionof the transfer layer 31 where removal is intended cannot be accuratelyremoved.

Furthermore, even if the peel-off layer 4 contains a vinyl chloride-typeresin and an acrylic-type resin, if the mass of the vinyl chloride-typeresin based on the total mass of the peel-off layer 4 is more than 95%by mass, the adhesion between the transfer layer 31 of the intermediatetransfer medium 30 and the peel-off layer 4 will be excessively strong.As a result, as shown in FIG. 3, it is likely that the peel-off layer 4that should originally remain on the thermal transfer sheet 10 will betaken by the intermediate transfer medium 30.

Furthermore, even if the peel-off layer 4 contains more than 50% by massand not more than 95% by mass of the vinyl chloride-type resin based onthe total mass of the peel-off layer 4, if it does not contain anacrylic-type resin, the adhesion between the substrate 1 and thepeel-off layer 4 will decrease. As a result, as shown in FIG. 3, it islikely that the peel-off layer 4 that should originally remain on thethermal transfer sheet 10 will be taken by the intermediate transfermedium 30.

The mechanism by which the peel-off property is improved by including avinyl chloride-type resin and an acrylic-type resin, and setting thecontent of the vinyl chloride-type resin to be more than 50% by mass andnot more than 95% by mass based on the total mass of the peel-off layer,has not been revealed yet. However, at least the fact that the contentof the vinyl chloride-type resin, and the acrylic-type resin used incombination with the vinyl chloride-type resin affect the peel-offproperty, has been revealed from the results of the examples andcomparative examples described below.

The peel-off layer 4 according to a first preferred embodiment containsnot less than 70% by mass and not more than 90% by mass, andparticularly not less than 80% by mass and not more than 90% by mass, ofthe vinyl chloride-type resin, based on the total mass of the peel-offlayer 4.

<Vinyl Chloride-Type Resin>

As used herein, “vinyl chloride-type resin” means a polymer obtained byhomopolymerization of vinyl chloride, a copolymer between vinyl chlorideand another monomer copolymerizable with vinyl chloride, and a mixtureof the polymer and the copolymer. Examples of another monomercopolymerizable with vinyl chloride include vinylidene chloride,ethylene, propylene, acrylonitrile, maleic acid, itaconic acid, acrylicacid, methacrylic acid, and vinyl acetate. These vinyl chloride-typeresins may be produced using any of known production methods such as anemulsion polymerization method, a suspension polymerization method, asolution polymerization method, and a block polymerization method. Thesevinyl chloride-type resins may also be produced using a method otherthan the above.

Among these vinyl chloride-type resins, a vinyl chloride-vinyl acetatecopolymer can be said to be a preferred vinyl chloride-type resin,because it can further improve the peel-off property.

Cured vinyl chloride-type resins obtained by curing the above-describedvinyl chloride-type resins with a curing agent can also be used as thevinyl chloride-type resin. Examples of the curing agent includeisocyanate-type curing agents.

The peel-off layer 4 according to the first preferred embodimentcontains a vinyl chloride-type resin having a number average molecularweight (Mn) of not less than 10000 and not more than 30000. Furthermore,the peel-off layer 4 according to the first preferred embodimentcontains a vinyl chloride-type resin having a glass transitiontemperature Tg of not less than 60° C. and not more than 80° C. Thepeel-off layer 4 according to the first preferred embodiment can furtherimprove the peel-off property. As used herein, “number average molecularweight (Mn)” means an average molecular weight measured by GPC in termsof polystyrene standards, in accordance with JIS-K7252-1 (2008). Thesame also applies to the below-described weight average molecular weight(Mw). As used herein, “glass transition temperature (Tg)” means atemperature determined based on measurement of a change in the amount ofheat by DSC (Differential Scanning calorimetry) (DSC method), inaccordance with JIS-K-7121 (2012).

<Acrylic-Type Resin>

As used herein, “acrylic-type resin” means a polymer of a monomer ofacrylic acid or methacrylic acid, or a derivative thereof, a polymer ofa monomer of an acrylic acid ester or methacrylic acid ester, or aderivative thereof, a copolymer of a monomer of acrylic acid ormethacrylic acid with another monomer, or a derivative thereof, acopolymer of a monomer of an acrylic acid ester or methacrylic acidester with another monomer, or a derivative thereof, a copolymer of amonomer of acrylic acid and a monomer of an acrylic acid ester, acopolymer of a monomer of acrylic acid and a monomer of a methacrylicacid ester, a copolymer of a monomer of methacrylic acid and a monomerof an acrylic acid ester, and a copolymer of a monomer of methacrylicacid and a monomer of a methacrylic acid ester.

Examples of monomers of acrylic acid esters and methacrylic acid estersinclude cyclohexyl acrylate, cyclohexyl methacrylate, benzyl acrylate,benzyl methacrylate, phenoxyethyl acrylate, phenoxyethyl methacrylate,isobornyl acrylate, isobornyl methacrylate, dicyclopentenyl acrylate,dicyclopentenyl methacrylate, methyl acrylate, methyl methacrylate,ethyl acrylate, ethyl methacrylate, propyl acrylate, propylmethacrylate, butyl acrylate, butyl methacrylate, isobutyl acrylate,isobutyl methacrylate, tert-butyl acrylate, tert-butyl methacrylate,isodecyl acrylate, isodecyl methacrylate, lauryl acrylate, laurylmethacrylate, lauryl tridecyl acrylate, lauryl tridecyl methacrylate,tridecyl acrylate, tridecyl methacrylate, cetyl stearyl acrylate, cetylstearyl methacrylate, stearyl acrylate, stearyl methacrylate,2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, octyl acrylate, octylmethacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, benzylacrylate, benzyl methacrylate, phenoxyethyl acrylate, phenoxyethylmethacrylate, methacrylic acid, acrylic acid, 2-hydroxyethyl acrylate,2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropylmethacrylate, dimethylaminoethyl acrylate, dimethylaminoethylmethacrylate, diethylaminoethyl acrylate, diethylaminoethylmethacrylate, tert-butylaminoethyl acrylate, tert-butylaminoethylmethacrylate, glycidyl acrylate, glycidyl methacrylate,tetrahydrofurfuryl acrylate, tetrahydrofurfuryl methacrylate, ethylenediacrylate, ethylene dimethacrylate, diethylene glycol diacrylate,diethylene glycol dimethacrylate, triethylene glycol diacrylate,triethylene glycol dimethacrylate, tetraethylene glycol diacrylate,tetraethylene glycol dimethacrylate, decaethylene glycol diacrylate,decaethylene glycol dimethacrylate, pentadecaethylene glycol diacrylate,pentadecaethylene glycol dimethacrylate, pentacontahectaethylene glycoldiacrylate, pentacontahectaethylene glycol dimethacrylate, butylenediacrylate, butylene dimethacrylate, allyl acrylate, allyl methacrylate,trimethylolpropane triacrylate, trimethylolpropane trimethacrylate,1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, tripropyleneglycol diacrylate, tripropylene glycol dimethacrylate, pentaerythritoltetraacrylate, pentaerythritol tetramethacrylate, dipentaerythritolhexaacrylate, dipentaerythritol hexamethacrylate, neopentyl glycolpentaacrylate, neopentyl glycol pentamethacrylate, phosphazenehexaacrylate, and phosphazene hexamethacrylate.

Examples of another monomer include aromatic hydrocarbons, arylgroup-containing compounds, amide group-containing compounds, vinylchloride, and the like; and styrene, benzylstyrene, phenoxyethylmethacrylate, acrylamide, methacrylamide, and the like.

Furthermore, as the acrylic-type resin, for example, an acrylic-typepolyol resin or the like can be used that is obtained by copolymerizingone or more acrylic acid alkyl esters, one or more (meth)acrylic acidesters having hydroxyl groups in their molecules such as 2-hydroxyethyl(meth)acrylate, 2-hydroxybutyl (meth)acrylate, and2-hydroxy-3-phenoxypropyl (meth)acrylate, and optionally one or moreother polymerizable monomers such as styrene.

The peel-off layer 4 according to the first preferred embodimentcontains an acrylic-type resin having a weight average molecular weight(Mw) of not less than 20000 and not more than 50000. Furthermore, thepeel-off layer 4 according to the first preferred embodiment contains anacrylic-type resin having a glass transition temperature (Tg) of notless than 80° C. and not more than 120° C. The peel-off layer 4according to the first preferred embodiment can further improve thepeel-off property.

Cured acrylic-type resins obtained by curing the above-describedacrylic-type resins with a curing agent can also be used as theacrylic-type resin. Examples of the curing agent include isocyanate-typecuring agents.

While there is no particular limitation on the content of theacrylic-type resin, the content of the acrylic-type resin is preferablynot less than 10% by mass and not more than 30% by mass, based on thetotal mass of the peel-off layer 4 according to the first embodiment.

The peel-off layer 4 according to the first embodiment may contain othercomponents along with the vinyl chloride-type resin and the acrylic-typeresin. Examples of the other components include natural or syntheticresins, for example, polyester-type resins; cellulosic resins such asethyl cellulose, hydroxy cellulose, hydroxypropylcellulose, methylcellulose, cellulose acetate, cellulose acetate butyrate, and nitrocellulose; vinyl-type resins such as polyvinyl alcohol, polyvinylacetate, polyvinyl butyral, polyvinyl acetal, and polyvinyl pyrrolidone;acrylic resins such as polymethyl methacrylate, polyethyl acrylate,polyacrylamide, and acrylonitrile-styrene copolymer; polyamide resin;polyvinyl toluene resin; coumarone-indene resin; polyurethane resin; andsilicone-modified or fluorine-modified urethane. These resins may beused alone or as a mixture, for example.

There is no particular limitation on the method for forming the peel-offlayer 4 according to the first embodiment. The peel-off layer 4according to the first embodiment can be formed by preparing a peel-offlayer coating liquid containing the vinyl chloride-type resin and theacrylic-type resin, as well as optionally additives such as any resinand an inorganic or organic filler, and applying this coating liquidonto the substrate 1 or any layer provided on the substrate 1, followedby drying. There is no particular limitation on the coating method forthe peel-off layer coating liquid, and a method selected as appropriatefrom known coating methods can be used. Examples of coating methodsinclude a gravure printing method, a screen printing method, and areverse coating method using a gravure plate. A coating method otherthan the above can also be used. The same also applies to the coatingmethod to be used for the below-described various coating liquids.

While there is no particular limitation on the thickness of the peel-offlayer 4 according to the first embodiment, the thickness is preferablynot less than 0.1 μm and not more than 5 μm. The same also applies tothe below-described peel-off layer 4 according to a second embodiment.

Peel-Off Layer According to a Second Embodiment

Instead of the peel-off layer 4 according to the first embodimentdescribed above, the peel-off layer 4 according to the second embodimentcan be used that contains a polyester-type resin having a number averagemolecular weight (Mn) of not more than 17000, and having a glasstransition temperature (Tg) of not less than 50° C. and not more than120° C. With the thermal transfer sheet 10 having the peel-off layer 4according to the second embodiment, a predetermined region of thetransfer layer 31 where removal is intended can be accurately removed.In particular, even if the thickness of the transfer layer 31 isincreased, a predetermined region of the transfer layer 31 where removalis intended can be accurately removed. Herein, the simple recitation“peel-off layer” includes both of the peel-off layer according to thefirst embodiment and the peel-off layer according to the secondembodiment.

In the peel-off layer 4 according to the second embodiment, thepolyester-type resin contained therein is a polyester-type resin thatsatisfies the following conditions 1 and 2:

Condition 1: the number average molecular weight (Mn) of thepolyester-type resin is not more than 17000.

Condition 2: the glass transition temperature (Tg) of the polyester-typeresin is not less than 50° C. and not more than 120° C.

Hereinafter, a polyester-type resin that satisfies the conditions 1 and2 may be referred to as a “specific polyester-type resin”.

A sufficiently satisfactory peel-off property cannot be obtained if thepeel-off layer contains, instead of the “specific polyester-type resin”,a polyester-type resin that does not satisfy either one or both of theconditions 1 and 2, or a resin different from the “specificpolyester-type resin”. Specifically, the transfer layer positioned nearthe boundary between a non-removal region and a removal region of thetransfer layer where removal by the peel-off layer is intended cannot beaccurately removed, and a portion of the removal region of the transferlayer that should be originally removed is likely to remain on theintermediate transfer medium. As a result, a predetermined region of thetransfer layer 31 where removal is intended cannot be accuratelyremoved. Alternatively, with the boundary between a removal region and anon-removal region as a start point, a portion of the transfer layer inthe non-removal region is removed in such a manner as to trail thetransfer layer in the non-removal region, and the transfer layer thatshould originally remain on the intermediate transfer medium, that is,the transfer layer in the non-removal region, is removed along with thetransfer layer corresponding to the removal region. As a result, apredetermined region of the transfer layer 31 where removal is intendedcannot be accurately removed.

The mechanism by which the peel-off property is improved by using thepeel-off layer 4 according to the second embodiment containing the“specific polyester-type resin” has not been revealed yet. However, atleast the fact that the number average molecular weight (Mn) and theglass transition temperature (Tg) of the polyester-type resin affect thepeel-off property has been revealed from the results of the examples andcomparative examples described below.

As used herein, “polyester-type resin” includes polymers containingester groups obtained by polycondensation between polybasic carboxylicacids and polyhydric alcohols. Examples of polybasic carboxylic acidsinclude terephthalic acid, isophthalic acid, phthalic acid,2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid,decanedicarboxylic acid, azelaic acid, dodecadicarboxylic acid, andcyclohexanedicarboxylic acid. Examples of polyhydric alcohols includeethylene glycol, propanediol, butanediol, pentanediol, hexanediol,neopentyl glycol, 1,4-cyclohexanedimethanol, decanediol,2-ethyl-butyl-1-propanediol, and bisphenol A. The polyester-type resinmay also be a copolymer of three or more polybasic carboxylic acids andpolyhydric alcohols, or a copolymer with a monomer or polymer such asdiethylene glycol, triethylene glycol, or polyethylene glycol. Thepolyester-type resin as used herein also includes modified products ofthe above-described polyester-type resins. Examples of modified productsof the polyester-type resins include polyester urethane resins.

The peel-off layer 4 according to the second embodiment may also containother components along with the “specific polyester-type resin”.Examples of the other components include polyester-type resins that donot satisfy either one or both of the conditions 1 and 2, and the othercomponents described above for the peel-off layer 4 according to thefirst embodiment.

Furthermore, the peel-off layer 4 according to the second embodiment maycontain two or more “specific polyester-type resins” having differentnumber average molecular weights (Mn) or glass transition temperatures(Tg), while satisfying the conditions 1 and 2.

There is no particular limitation on the content of the “specificpolyester-type resin”. The peel-off property can be improved simply byincluding the “specific polyester-type resin” in the peel-off layer 4,regardless of its content. By way of example, the content of the“specific polyester-type resin” is not less than 5% by mass, preferablynot less than 10% by mass, more preferably not less than 15% by mass,and particularly preferably not less than 20% by mass, based on thetotal mass of the peel-off layer 4 according to the second embodiment.The upper limit of the content of the “specific polyester-type resin” isnot limited, and is 100% by mass.

The lower limit of the number average molecular weight (Mn) of the“specific polyester-type resin” is not particularly limited, and ispreferably not less than 2500, and more preferably not less than 3500.

The peel-off layer 4 according to a second preferred embodimentcontains, as the “specific polyester-type resin”, a polyester-type resinthat has a number average molecular weight (Mn) of less than 9000, morepreferably not more than 8000, and satisfies the condition 2.Furthermore, the peel-off layer 4 according to the second preferredembodiment contains, as the “specific polyester-type resin”, a polyesterresin that satisfies the condition 1, and has a glass transitiontemperature (Tg) of not less than 50° C. and not more than 100° C. Thepeel-off layer 4 according to a particularly preferred second embodimentcontains, as the “specific polyester-type resin”, a polyester resin thathas a number average molecular weight (Mn) of less than 9000, morepreferably not more than 8000, and has a glass transition temperature(Tg) of not less than 50° C. and not more than 100° C. The peel-offlayers 4 according to these second preferred embodiments can furtherimprove the peel-off property.

There is no particular limitation on the method for forming the peel-offlayer 4 according to the second embodiment. The peel-off layer 4according to the second embodiment can be formed by preparing a peel-offlayer coating liquid containing the “specific polyester-type resin”, aswell as optionally additives such as any resin and an inorganic ororganic filler, and applying this coating liquid onto the substrate 1 orany layer provided on the substrate 1, followed by drying.

(Primer Layer)

As shown in FIG. 1, the primer layer 2 may be provided between thesubstrate 1 and the peel-off layer 4. The provision of the primer layer2 between the substrate 1 and the peel-off layer 4 can sufficientlyinhibit the so-called reverse transfer of the peel-off layer in which,upon removing a predetermined region of the transfer layer 31 by meansof the peel-off layer 4, the peel-off layer 4 that should originallyremain on the thermal transfer sheet 10 along with the removed transferlayer is transferred onto the intermediate transfer medium. Inparticular, the reverse transfer of the peel-off layer tends to occurwhen the energy applied to the thermal transfer sheet for removing thetransfer layer of the intermediate transfer medium by means of thepeel-off layer is increased. In this case, therefore, it is preferred toprovide the primer layer 2.

Examples of materials forming the primer layer 2 include polyester-typeresins, polyacrylic ester-type resins, polyvinyl acetate-type resins,polyurethane-type resins, styrene acrylate-type resins,polyacrylamide-type resins, polyamide-type resins, polyether-typeresins, polystyrene-type resins, polyethylene-type resins,polypropylene-type resins, vinyl-type resins such as polyvinyl chlorideresin, polyvinyl alcohol-type resins, and polyvinyl pyrrolidone,polyvinyl acetal-type resins such as polyvinyl acetoacetal and polyvinylbutyral, and inorganic particles.

The thickness of the primer layer 2 is preferably not less than 0.03 μm,and more preferably not less than 0.06 μm. While the upper limit of thethickness of the primer layer 2 is not particularly limited, it is about1 μm.

There is no particular limitation on the method for forming the primerlayer 2. The primer layer 2 can be formed by preparing a primer layercoating liquid by dissolving or dispersing any of the above-exemplifiedmaterials and the like in a suitable solvent, and applying this coatingliquid onto the substrate 1, followed by drying.

(Back Face Layer)

As shown in FIG. 1, the back face layer 5 may be provided on the othersurface of the substrate 1. The back face layer 5 is an optionalconstituent in the thermal transfer sheet 10 according to an embodiment.

There is no limitation on the material of the back face layer 5, andexamples include natural or synthetic resins, for example, cellulosicresins such as ethyl cellulose, hydroxy cellulose,hydroxypropylcellulose, methyl cellulose, cellulose acetate, celluloseacetate butyrate, and nitro cellulose; vinyl-type resins such aspolyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinylacetal, and polyvinyl pyrrolidone; acrylic-type resins such aspolymethyl methacrylate, polyethyl acrylate, polyacrylamide, andacrylonitrile-styrene copolymer; polyamide resin; polyvinyl tolueneresin; coumarone-indene resin; polyester-type resins, polyurethaneresin; and silicone-modified or fluorine-modified urethane. These resinsmay be used alone or as a mixture, for example.

The back face layer 5 may also contain a solid or liquid lubricant.Examples of the lubricant include various waxes such as polyethylene waxand paraffin wax, higher aliphatic alcohols, organopolysiloxanes,anionic surfactants, cationic surfactants, amphoteric surfactants,nonionic surfactants, fluorine-type surfactants, organic carboxylicacids and derivatives thereof, metal soaps, fluorine-type resins,silicone-type resins, and fine particles of inorganic compounds such astalc and silica. The mass of the lubricant based on the total mass ofthe back face layer 5 is not less than 5% by mass and not more than 50%by mass, and preferably not less than 10% by mass and not more than 30%by mass.

There is no particular limitation on the method for forming the backface layer 5. The back face layer 5 can be formed by preparing a backface layer coating liquid by dissolving or dispersing the resin, anoptionally added lubricant, and the like in a suitable solvent, andapplying this coating liquid onto the substrate 1, followed by drying.The thickness of the back face layer 5 is preferably not less than 1 μmand not more than 10 μm.

As shown in FIG. 4, the thermal transfer sheet 10 according to anembodiment may have a structure in which respective dye layers 7 ofyellow (Y), magenta (M), and cyanogen (C) (7(Y), 7(M), and 7(C)), and afusible layer 8 of black (Bk) are provided in a frame sequential manner,on the same surface of the substrate 1 as that having the peel-off layer4. The dye layers 7 and the fusible layer 8 are optional constituents inthe thermal transfer sheet 10 according to an embodiment. Furthermore, atransferable protective layer (not illustrated) may be provided in placeof these optional layers, or in a frame sequential manner along withthese layers.

(Dye Layers)

Each of the dye layers 7 contains a sublimable dye, a binder resin, andoptionally added components. The sublimable dye, the binder resin, andthe like are not particularly limited, and known ones can be used. Eachof the dye layers can be formed by preparing a dye layer coating liquidby dissolving or dispersing the sublimable dye, the binder resin, andoptionally added components in a suitable solvent, and applying thiscoating liquid onto the substrate 1, followed by drying. The thicknessof each of the dye layers is usually not less than 0.2 μm and not morethan 3 μm.

Furthermore, a known dye primer layer (not illustrated) may be providedbetween the substrate 1 and the dye layers 7.

(Fusible Layer)

The fusible layer 8 can be formed using a known thermally fusible ink,and optionally contains various additives. These materials are notparticularly limited, and known ones can be used. The fusible layer 8 isformed by applying the thermally fusible ink onto the substrate 1 usinga method such as a gravure printing method or hot-melt coating, followedby drying. The thickness of the fusible layer is determined based on therelationship between the required density and the thermal sensitivity,and is usually not less than about 0.2 μm and not more than about 10 μm.

<Peel-Off Region>

Next, referring to FIG. 5, an example of the removal region of thetransfer layer to be removed by the peel-off layer 4 of the thermaltransfer sheet 10 according to an embodiment will be described. FIG. 5is a schematic plan view of the intermediate transfer medium 30 for usein combination with the thermal transfer sheet 10 according to anembodiment. The blank regions (indicated by the symbols “A” and “B” inthe figure) are the regions that have been removed by the peel-off layer4 of the thermal transfer sheet 10 according to an embodiment.

There is no particular limitation on the regions of the transfer layer31 to be removed, and examples of the regions to be removed includeperipheral portions of the transfer layer 31 to be transferred onto atransfer receiving article, as indicated by the symbol “A” in FIG. 5. Inother words, the regions that are not to be transferred onto a transferreceiving article can be removed by the peel-off layer 4 to remove theedges. Furthermore, as indicated by the symbol “B” in FIG. 5, examplesof the regions to be removed also include a region where an accessorysuch as an IC chip or a signature portion is to be mounted on thetransfer receiving article onto which the transfer layer 31 is to befinally transferred, that is, a region that causes inconvenience if thatregion of the transfer layer 31 remains on the transfer receivingarticle onto which the transfer layer 31 has been transferred.

<Heating Method>

There is no particular limitation on the heating device for removing apredetermined region of the transfer layer 31 by means of the peel-offlayer 4. For example, a thermal head, or a heating device that uses alight source or a laser light source can be used. Furthermore, there isno limitation on the heating device for re-transferring the transferlayer 31, from which the predetermined region has been removed by thepeel-off layer 4, onto a transfer receiving article. For example, a heatroll method, a hot stamping method, or a thermal head method can beused.

The intermediate transfer medium for use in combination with the thermaltransfer sheet 10 according to an embodiment is not limited to theillustrated embodiment, and any known intermediate transfer medium isapplicable. Furthermore, instead of the intermediate transfer medium, aprotective layer transfer sheet in which a transfer layer including aprotective layer is provided on a support may be used.

<<Combination of Transfer Foil and Thermal Transfer Sheet>>

Next, a combination of a transfer foil and a thermal transfer sheetaccording to an embodiment of the present disclosure (hereinafterreferred to as the combination according to an embodiment) will bedescribed. The combination according to an embodiment is a combinationof a transfer foil in which a transfer layer is provided on a supportsuch that the transfer layer can be peeled off from the support, and athermal transfer sheet in which a peel-off layer is provided on asubstrate, wherein under conditions in which the transfer foil and thethermal transfer sheet are superposed on each other such that thetransfer layer and the peel-off layer are opposed to each other, and atransport speed for the thermal transfer sheet is set to 42.3 mm/sec,and energy applied to the thermal transfer sheet is set to 0.143 mJ/dot,adhesion between the transfer layer and the peel-off layer as measuredwhen a predetermined region of the transfer layer is removed by means ofthe peel-off layer is not less than 0.03 N/cm. Hereinafter, theconditions in which the transfer foil and the thermal transfer sheet aresuperposed on each other such that the transfer layer and the peel-offlayer are opposed to each other, and the transport speed for the thermaltransfer sheet is set to 42.3 mm/sec, and the energy applied to thethermal transfer sheet is set to 0.143 mJ/dot, may be referred to as the“specific measurement conditions”. The adhesion between the transferlayer and the peel-off layer as measured when a predetermined region ofthe transfer layer is removed by means of the peel-off layer under the“specific measurement conditions” may be referred to as the adhesionbetween the transfer layer and the peel-off layer.

Under the “specific measurement conditions”, a predetermined region ofthe transfer layer is removed by the peel-off layer such that the peelangle of the transfer layer to be peeled off from the support becomes50°.

With the combination according to an embodiment in which the adhesionbetween the transfer layer and the peel-off layer measured under the“specific measurement conditions” is not less than 0.03 N/cm, apredetermined region of the transfer layer can be accurately removed bythe peel-off layer.

In the combination according to a preferred embodiment, the adhesionbetween the transfer layer and the peel-off layer measured under the“specific measurement conditions” is not less than 0.05 N/cm, preferablynot less than 0.18 N/cm, and more preferably not less than 0.2 N/cm. Inthe combination according to a particularly preferred embodiment, theadhesion between the transfer layer and the peel-off layer measured uponremoving a predetermined region of the transfer layer by means of thepeel-off layer, under conditions in which the transport speed for thethermal transfer sheet is set to 42.3 mm/sec, and the energy applied tothe thermal transfer sheet is set to not less than 0.1 mJ/dot and notmore than 0.2 mJ/dot, is not less than 0.03 N/cm, and in particular, theadhesion is as mentioned above in the combination according to apreferred embodiment. There is no particular limitation on the upperlimit of the adhesion between the transfer layer and the peel-off layermeasured under the “specific measurement conditions”. For example, theadhesion may be not less than 0.03 N/cm and not more than 1 N/cm, or notless than 0.03 N/cm and not more than 0.7 N/cm.

In the combination according to an embodiment, the adhesion between thetransfer layer and the peel-off layer is the value of tensile strengthmeasured as follows: The transfer layer of the transfer foil and thepeel-off layer of the thermal transfer sheet are superposed on eachother, and, as shown in FIG. 6, using a printer 200 having a thermaltransfer sheet feed device 201, a heating device 202, a thermal transfersheet take-up device 203, a measurement device 204 positioned betweenthe heating device 202 and the thermal transfer sheet take-up device 203to measure the tensile strength of the thermal transfer sheettransported along the transport path, and a peel device 205 positionedbetween the heating device 202 and the measurement device 204, the valueof tensile strength is measured by the measurement device 204 uponremoving the transfer layer of the transfer foil by means of thepeel-off layer of the thermal transfer sheet, under the conditions inwhich the transport speed for the thermal transfer sheet is 42.3 mm/sec,and the applied energy for the thermal transfer sheet is 0.143 mJ/dot.This value of tensile strength can be defined as the adhesion betweenthe transfer layer and the peel-off layer.

As used herein, “applied energy (mJ/dot)” is the applied energycalculated based on the following equation (1), and the applied electricpower [W] in the equation (1) can be calculated based on the followingequation (2):

Applied energy (mJ/dot)=W×L·S×P·D×gray-scale value   (equation (1))

wherein [W] denotes the applied electric power, [L·S] denotes one lineperiod (msec/line), and [P·D] denotes the pulse duty.

Applied electric power (W/dot)=V ² /R  (equation (2))

wherein [V] denotes the applied voltage, and [R] denotes the resistanceof the heating device.

As used herein, “transport speed (mm/sec)” for the thermal transfersheet is the transport speed calculated based on the following equation(3):

Transport speed (mm/sec)=(25.4×1000)/(print density in the verticalscanning direction (dot/inch)×line period (msec/line))   (equation (3))

wherein 25.4 is the value for converting inch to mm.

There is no particular limitation on the method for setting the adhesionbetween the transfer layer and the peel-off layer to not less than 0.03N/cm. Examples of measures taken for the thermal transfer sheet includeadjusting the components of the peel-off layer, or adjusting thethickness of the peel-off layer or the substrate. Examples of measurestaken for the transfer foil include adjusting the components of thetransfer layer, or adjusting the thickness of the transfer layer.Furthermore, the adhesion between the transfer layer and the peel-offlayer can be set to not less than 0.03 N/cm by taking measures for bothof the thermal transfer sheet and the transfer foil.

That is, as long as the transfer foil and the thermal transfer sheetused in the combination according to an embodiment satisfy the conditionthat the adhesion between the transfer layer and the peel-off layermeasured under the “specific measurement conditions” is not less than0.03 N/cm, no limitation is placed on the transfer foil and the thermaltransfer sheet with respect to conditions other than the above.

There is no particular limitation on the applications of the transferfoil used in the combination according to an embodiment. Examples of theapplications include an intermediate transfer medium that can transfer atransfer layer including a receiving layer onto a transfer receivingarticle, and a protective layer transfer sheet that can transfer atransfer layer including a protective layer onto a transfer receivingarticle. Furthermore, any medium other than the above that can transfera transfer layer onto a transfer receiving article can be used.

EXAMPLES

Next, the present invention will be described more specifically withreference to examples. Hereinafter, “part(s)” means part(s) by mass,unless otherwise specified. “Tg” means the glass transition temperature,“Mn” means the number average molecular weight, and “Mw” means theweight average molecular weight.

Example A-1

As a substrate, a 4.5-μm-thick polyethylene terephthalate film subjectedto an easy adhesion treatment in advance was used, and a peel-off layercoating liquid 1 of the composition shown below was applied onto onesurface, i.e., the easy adhesion-treated surface, of the substrate togive a thickness of 1 μm in a dried state, and dried to form a peel-offlayer. Furthermore, a back face layer coating liquid of the compositionshown below was applied onto the other surface of the substrate to givea thickness of 0.8 μm in a dried state, and dried to form a back facelayer. As a result, a thermal transfer sheet according to Example A-1was obtained.

<Peel-off layer coating liquid 1>

Vinyl chloride-vinyl acetate copolymer 14 parts (Mn: 12000, Tg: 76° C.)(SOLBIN (registered trademark) CNL; Nisshin Chemical Co., Ltd.) Acrylicresin (Mw: 25000, Tg: 105° C.)  6 parts (DIANAL (registered trademark)BR87; Mitsubishi Rayon Co., Ltd.) Methyl ethyl ketone 80 parts

<Back Face Layer Coating Liquid>

Polyvinyl butyral resin    2 parts (S-LEC (registered trademark) BX-1;Sekisui Chemical Co., Ltd.) Polyisocyanate  9.2 parts (BURNOCK(registered trademark) D750; DIC Corporation) Phosphoric ester-typesurfactant  1.3 parts (PLYSURF (registered trademark) A208N; DKS Co.,Ltd) Talc  0.3 part (MICRO ACE (registered trademark) P-3; Nippon TalcCo., Ltd.) Toluene 43.6 parts Methyl ethyl ketone 43.6 parts

Example A-2

A thermal transfer sheet according to Example A-2 was obtained as inExample A-1, except that the peel-off layer coating liquid 1 wasreplaced with a peel-off layer coating liquid 2 of the composition shownbelow.

<Peel-Off Layer Coating Liquid 2>

Vinyl chloride-vinyl acetate copolymer 18 parts (Mn: 12000, Tg: 76° C.)(SOLBIN (registered trademark) CNL; Nisshin Chemical Co., Ltd.) Acrylicresin (Mw: 25000, Tg: 105° C.)  2 parts (DIANAL (registered trademark)BR87; Mitsubishi Rayon Co., Ltd.) Methyl ethyl ketone 80 parts

Example A-3

A thermal transfer sheet according to Example A-3 was obtained as inExample A-1, except that the peel-off layer coating liquid 1 wasreplaced with a peel-off layer coating liquid 3 of the composition shownbelow.

<Peel-Off Layer Coating Liquid 3>

Vinyl chloride-vinyl acetate copolymer 14 parts (Mn: 27000, Tg: 68° C.)(SOLBIN (registered trademark) C5R; Nisshin Chemical Co., Ltd.) Acrylicresin (Mw: 40000, Tg: 105° C.)  6 parts (DIANAL (registered trademark)BR83; Mitsubishi Rayon Co., Ltd.) Methyl ethyl ketone 80 parts

Example A-4

A thermal transfer sheet according to Example A-4 was obtained as inExample A-1, except that the peel-off layer coating liquid 1 wasreplaced with a peel-off layer coating liquid 4 of the composition shownbelow.

<Peel-Off Layer Coating Liquid 4>

Vinyl chloride-vinyl acetate copolymer 14 parts (Mn: 12000, Tg: 76° C.)(SOLBIN (registered trademark) CNL; Nisshin Chemical Co., Ltd.) Acrylicresin (Mw: 25000, Tg: 105° C.)  4 parts (DIANAL (registered trademark)BR87; Mitsubishi Rayon Co., Ltd.) Polyester resin  2 parts (UE-9885;Unitika Ltd.) Methyl ethyl ketone 80 parts

Example A-5

A thermal transfer sheet according to Example A-5 was obtained as inExample A-1, except that the peel-off layer coating liquid 1 wasreplaced with a peel-off layer coating liquid 5 of the composition shownbelow.

<Peel-Off Layer Coating Liquid 5>

Vinyl chloride-vinyl acetate copolymer 11 parts (Mn: 12000, Tg: 76° C.)(SOLBIN (registered trademark) CNL; Nisshin Chemical Co., Ltd.) Acrylicresin (Mw: 25000, Tg: 105° C.)  9 parts (DIANAL (registered trademark)BR87; Mitsubishi Rayon Co., Ltd.) Methyl ethyl ketone 80 parts

Comparative Example A-1

A thermal transfer sheet according to Comparative Example A-1 wasobtained as in Example A-1, except that the peel-off layer coatingliquid 1 was replaced with a peel-off layer coating liquid A of thecomposition shown below.

<Peel-Off Layer Coating Liquid A>

Acrylic resin (Mw: 25000, Tg: 105° C.) 20 parts (DIANAL (registeredtrademark) BR87; Mitsubishi Rayon Co., Ltd.) Methyl ethyl ketone 80parts

Comparative Example A-2

A thermal transfer sheet according to Comparative Example A-2 wasobtained as in Example A-1, except that the peel-off layer coatingliquid 1 was replaced with a peel-off layer coating liquid B of thecomposition shown below.

<Peel-Off Layer Coating Liquid B>

Vinyl chloride-vinyl acetate copolymer 10 parts (Mn: 12000, Tg: 76° C.)(SOLBIN (registered trademark) CNL; Nisshin Chemical Co., Ltd.) Acrylicresin (Mw: 25000, Tg: 105° C.) 10 parts (DIANAL (registered trademark)BR87; Mitsubishi Rayon Co., Ltd.) Methyl ethyl ketone 80 parts

Comparative Example A-3

A thermal transfer sheet according to Comparative Example A-3 wasobtained as in Example A-1, except that the peel-off layer coatingliquid 1 was replaced with a peel-off layer coating liquid C of thecomposition shown below.

<Peel-Off Layer Coating Liquid C>

Vinyl chloride-vinyl acetate copolymer 10 parts (Mn: 27000, Tg: 68° C.)(SOLBIN (registered trademark) C5R; Nisshin Chemical Co., Ltd.) Acrylicresin (Mw: 40000, Tg: 105° C.) 10 parts (DIANAL (registered trademark)BR87; Mitsubishi Rayon Co., Ltd.) Methyl ethyl ketone 80 parts

Comparative Example A-4

A thermal transfer sheet according to Comparative Example A-4 wasobtained as in Example A-1, except that the peel-off layer coatingliquid 1 was replaced with a peel-off layer coating liquid D of thecomposition shown below.

<Peel-Off Layer Coating Liquid D>

Vinyl chloride-vinyl acetate copolymer 20 parts (Mn: 12000, Tg: 76° C.)(SOLBIN (registered trademark) CNL; Nisshin Chemical Co., Ltd.) Methylethyl ketone 80 parts

Comparative Example A-5

A thermal transfer sheet according to Comparative Example A-5 wasobtained as in Example A-1, except that the peel-off layer coatingliquid 1 was replaced with a peel-off layer coating liquid E of thecomposition shown below.

<Peel-Off Layer Coating Liquid E>

Vinyl chloride-vinyl acetate copolymer 19.6 parts (Mn: 12000, Tg: 76°C.) (SOLBIN (registered trademark) CNL; Nisshin Chemical Co., Ltd.)Acrylic resin (Mw: 25000, Tg: 105° C.)  0.4 part (DIANAL (registeredtrademark) BR87; Mitsubishi Rayon Co., Ltd.) Methyl ethyl ketone   80parts

(Preparation of Intermediate Transfer Medium (1))

As a support, a 12-μm-thick polyethylene terephthalate film (Lumirror(registered trademark); Toray, Industries, Inc.) was used, and a releaselayer coating liquid of the composition shown below was applied onto thesupport to give a thickness of 1.6 μm in a dried state, and dried toform a release layer. Then, a protective layer coating liquid of thecomposition shown below was applied onto the release layer to give athickness of 4.7 μm in a dried state, and dried to form a protectivelayer. Then, a receiving layer coating liquid of the composition shownbelow was applied onto the protective layer to give a thickness of 2 μmin a dried state, and dried to form a receiving layer. As a result, anintermediate transfer medium (1) was obtained. The release layer coatingliquid, the protective layer coating liquid, and the receiving layercoating liquid were all applied using a gravure printing method.

<Release Layer Coating Liquid>

Acrylic resin 20 parts (DIANAL (registered trademark) BR83; MitsubishiRayon Co., Ltd.) Polyester resin  1 part (Vylon (registered trademark)600; Toyobo Co., Ltd.) Methyl ethyl ketone 79 parts

<Protective Layer Coating Liquid>

Polyester resin 20 parts (Vylon (registered trademark) GK-250; ToyoboCo., Ltd.) Methyl ethyl ketone 80 parts

<Receiving Layer Coating Liquid>

Vinyl chloride-vinyl acetate copolymer 20 parts (SOLBIN (registeredtrademark) CNL; Nisshin Chemical Co., Ltd.) Silicone oil  1 part(X-22-3000T; Shin-Etsu Chemical Co., Ltd.) Methyl ethyl ketone 79 parts

<Peel-Off Property Test>

A photo-like thermal transfer image was formed by sublimation transferon the receiving layer of the intermediate transfer medium (1) preparedabove. Then, the receiving layer of the intermediate transfer medium (1)on which the thermal transfer image was formed and the peel-off layer ofthe thermal transfer sheet according to each of the examples andcomparative examples prepared above were superposed on each other tocontact each other. Using the printer shown below, the back surface sideof the thermal transfer sheet was heated to remove a predeterminedregion of the transfer layer composed of a layered structure of therelease layer, the protective layer, and the receiving layer from theintermediate transfer medium (1). At this time, the removal state of thetransfer layer and the release state upon releasing the peel-off layerfrom the intermediate transfer medium (1) were visually examined, andthe peel-off property and the release property of the peel-off layerwere evaluated based on the evaluation criteria shown below. Theevaluation results are shown in Table 1.

(Printer)

Thermal head: KEE-57-12GAN2-STA (KYOCERA Corporation)

Average resistance of the heating element: 3303 (Ω)

Print density in the horizontal scanning direction: 300 (dpi)

Print density in the vertical scanning direction: 300 (dpi)

Line period: 2 (msec/line)

Print start temperature: 35 (° C.)

Pulse Duty ratio: 85(%)

Applied voltage: 21 (V)

(Evaluation of Peel-Off Property (1))

“Evaluation Criteria”

-   -   A: The transfer layer corresponding to the “predetermined        region” was accurately removed.    -   B: The transfer layer was removed in such a manner that a        portion of the transfer layer corresponding to the        “predetermined region” slightly remained, or the transfer layer        slightly extended off the “predetermined region”; however, the        peel-off property was at a level that practically causes no        problem.    -   C: The transfer layer was removed in such a manner that a        portion of the transfer layer corresponding to the        “predetermined region” remained, or the transfer layer extended        off the “predetermined region”; however, the peel-off property        was at a level that practically causes no problem.    -   NG (1): The transfer layer corresponding to the “predetermined        region” was not accurately removed, and the peel-off property        was poor.    -   NG (2): The transfer layer corresponding to the “predetermined        region” was not removed at all, and the peel-off property was        poor.

(Evaluation of the Release Property of the Peel-Off Layer)

“Evaluation Criteria”

-   -   A: The peel-off layer was not transferred onto the intermediate        transfer medium.    -   NG: A portion of the peel-off layer was transferred onto the        intermediate transfer medium, and the release property was poor.

TABLE 1 Content (%) of Each Component (*1) Vinyl Chloride-TypeAcrylic-Type Peel-Off Release Resin Resin Property Property Example A-170 30 B A Example A-2 90 10 A A Example A-3 70 30 B A Example A-4 70 20A A Example A-5 55 45 B A Comparative Example A-1 — 100  NG (2) —Comparative Example A-2 50 50 NG (1) A Comparative Example A-3 50 50 NG(1) A Comparative Example A-4 100  — A NG Comparative Example A-5 98  2A NG (*1) The content of each of the vinyl chloride-type resin and theacrylic-type resin based on the total mass of the peel-off layer

Example B-1

As a substrate, a 4.5-μm-thick polyethylene terephthalate film subjectedto an easy adhesion treatment in advance was used, and a peel-off layercoating liquid 11 of the composition shown below was applied onto onesurface, i.e., the easy adhesion-treated surface, of the substrate togive a thickness of 1 μm in a dried state, and dried to form a peel-offlayer. Furthermore, the back face layer coating liquid of thecomposition shown above was applied onto the other surface of thesubstrate to give a thickness of 0.8 μm in a dried state, and dried toform a back face layer. As a result, a thermal transfer sheet accordingto Example B-1 was obtained.

<Peel-Off Layer Coating Liquid 11>

Polyester resin (Tg: 85° C., Mn: 8000) 20 parts (Vylon (registeredtrademark) 885; Toyobo Co., Ltd.) Methyl ethyl ketone 80 parts

Example B-2

A thermal transfer sheet according to Example B-2 was obtained as inExample B-1, except that the peel-off layer coating liquid 11 wasreplaced with a peel-off layer coating liquid 12 of the compositionshown below.

<Peel-Off Layer Coating Liquid 12>

Polyester resin (Tg: 82° C., Mn: 6000) 20 parts (UE-9885; Unitika Ltd.)Methyl ethyl ketone 80 parts

Example B-3

A thermal transfer sheet according to Example B-3 was obtained as inExample B-1, except that the peel-off layer coating liquid 11 wasreplaced with a peel-off layer coating liquid 13 of the compositionshown below.

<Peel-Off Layer Coating Liquid 13>

Polyester resin (Tg: 63° C., Mn: 8000) 20 parts (UE-3980; Unitika Ltd.)Methyl ethyl ketone 80 parts

Example B-4

A thermal transfer sheet according to Example B-4 was obtained as inExample B-1, except that the peel-off layer coating liquid 11 wasreplaced with a peel-off layer coating liquid 14 of the compositionshown below.

<Peel-Off Layer Coating Liquid 14>

Polyester resin (Tg: 53° C., Mn: 7000) 20 parts (UE-3370; Unitika Ltd.)Methyl ethyl ketone 80 parts

Example B-5

A thermal transfer sheet according to Example B-5 was obtained as inExample B-1, except that the peel-off layer coating liquid 11 wasreplaced with a peel-off layer coating liquid 15 of the compositionshown below.

<Peel-Off Layer Coating Liquid 15>

Polyester resin (Tg: 67° C., Mn: 17000) 20 parts (Vylon (registeredtrademark) 200; Toyobo Co., Ltd.) Methyl ethyl ketone 80 parts

Example B-6

A thermal transfer sheet according to Example B-6 was obtained as inExample B-1, except that the peel-off layer coating liquid 11 wasreplaced with a peel-off layer coating liquid 16 of the compositionshown below.

<Peel-Off Layer Coating Liquid 16>

Polyester resin (Tg: 65° C., Mn: 15000) 20 parts (UE-9200; Unitika Ltd.)Methyl ethyl ketone 80 parts

Example B-7

A thermal transfer sheet according to Example B-7 was obtained as inExample B-1, except that the peel-off layer coating liquid 11 wasreplaced with a peel-off layer coating liquid 17 of the compositionshown below.

<Peel-Off Layer Coating Liquid 17>

Polyester resin (Tg: 53° C., Mn: 3000) 20 parts (Vylon (registeredtrademark) 220; Toyobo Co., Ltd.) Methyl ethyl ketone 80 parts

Example B-8

A thermal transfer sheet according to Example B-8 was obtained as inExample B-1, except that the peel-off layer coating liquid 11 wasreplaced with a peel-off layer coating liquid 18 of the compositionshown below.

<Peel-Off Layer Coating Liquid 18>

Polyester resin (Tg: 82° C., Mn: 6000)  2 parts (UE-9885; Unitika Ltd.)Acrylic resin  9 parts (DIANAL (registered trademark) BR87; MitsubishiRayon Co., Ltd.) Vinyl chloride-vinyl acetate copolymer  9 parts (SOLBIN(registered trademark) CNL; Nisshin Chemical Co., Ltd.) Methyl ethylketone 80 parts

Example B-9

A thermal transfer sheet according to Example B-9 was obtained as inExample B-1, except that the peel-off layer coating liquid 11 wasreplaced with a peel-off layer coating liquid 19 of the compositionshown below.

<Peel-Off Layer Coating Liquid 19>

Polyester resin (Tg: 82° C., Mn: 6000) 4.8 parts (UE-9885; Unitika Ltd.)Acrylic resin 7.6 parts (DIANAL (registered trademark) BR87; MitsubishiRayon Co., Ltd.) Vinyl chloride-vinyl acetate copolymer 7.6 parts(SOLBIN (registered trademark) CNL; Nisshin Chemical Co., Ltd.) Methylethyl ketone  80 parts

Example B-10

A thermal transfer sheet according to Example B-10 was obtained as inExample B-1, except that the peel-off layer coating liquid 11 wasreplaced with a peel-off layer coating liquid 20 of the compositionshown below.

<Peel-Off Layer Coating Liquid 20>

Polyester resin (Tg: 101° C., Mn: 15000) 20 parts (UE-9900; UnitikaLtd.) Methyl ethyl ketone 80 parts

Comparative Example B-1

A thermal transfer sheet according to Comparative Example B-1 wasobtained as in Example B-1, except that the peel-off layer coatingliquid 11 was replaced with a peel-off layer coating liquid F of thecomposition shown below.

<Peel-Off Layer Coating Liquid F>

Acrylic resin 10 parts (DIANAL (registered trademark) BR87; MitsubishiRayon Co., Ltd.) Vinyl chloride-vinyl acetate copolymer 10 parts (SOLBIN(registered trademark) CNL; Nisshin Chemical Co., Ltd.) Methyl ethylketone 80 parts

Comparative Example B-2

A thermal transfer sheet according to Comparative Example B-2 wasobtained as in Example B-1, except that the peel-off layer coatingliquid 11 was replaced with a peel-off layer coating liquid G of thecomposition shown below.

<Peel-Off Layer Coating Liquid G>

Polyester resin (Tg: 46° C., Mn: 6000) 20 parts (Vylon (registeredtrademark) GK-810; Toyobo Co., Ltd.) Methyl ethyl ketone 80 parts

Comparative Example B-3

A thermal transfer sheet according to Comparative Example B-3 wasobtained as in Example B-1, except that the peel-off layer coatingliquid 11 was replaced with a peel-off layer coating liquid H of thecomposition shown below.

<Peel-Off Layer Coating Liquid H>

Polyester resin (Tg: 71° C., Mn: 18000) 20 parts (UE-9600; Unitika Ltd.)Methyl ethyl ketone 80 parts

Comparative Example B-4

A thermal transfer sheet according to Comparative Example B-4 wasobtained as in Example B-1, except that the peel-off layer coatingliquid 11 was replaced with a peel-off layer coating liquid I of thecomposition shown below.

<Peel-Off Layer Coating Liquid I>

Polyester resin (Tg: 40° C., Mn: 1800) 20 parts (UE-3320; Unitika Ltd.)Methyl ethyl ketone 80 parts

Comparative Example B-5

A thermal transfer sheet according to Comparative Example B-5 wasobtained as in Example B-1, except that the peel-off layer coatingliquid 11 was replaced with a peel-off layer coating liquid J of thecomposition shown below.

<Peel-Off Layer Coating Liquid J>

Polyester resin (Tg: −25° C., Mn: 34000) 20 parts (UE-3510; UnitikaLtd.) Methyl ethyl ketone 80 parts

Comparative Example B-6

A thermal transfer sheet according to Comparative Example B-6 wasobtained as in Example B-1, except that the peel-off layer coatingliquid 11 was replaced with a peel-off layer coating liquid K of thecomposition shown below.

<Peel-Off Layer Coating Liquid K>

Polyester resin (Tg: −70° C., Mn: 30000) 20 parts (Vylon (registeredtrademark) GM913; Unitika Ltd.) Methyl ethyl ketone 80 parts

(Preparation of Intermediate Transfer Medium (2))

An intermediate transfer medium (2) was prepared using the samepreparation method as that for the intermediate transfer medium (1),except that the release layer coating liquid was applied to give athickness of 0.7 μm in a dried state, and dried to form a release layer,the protective layer coating liquid of the composition shown above wasapplied to give a thickness of 1.5 μm in a dried state, and dried toform a protective layer, and the receiving layer coating liquid of thecomposition shown above was applied to give a thickness of 0.7 μm in adried state, and dried to form a receiving layer. As compared with theintermediate transfer medium (2), the intermediate transfer medium (1)has a greater total thickness of the transfer layer composed of alayered structure of the release layer, the protective layer, and thereceiving layer, and tends to have a lower peel-off property.

(Evaluation of Peel-Off Property (2))

A photo-like thermal transfer image was formed by sublimation transferon the receiving layer of the intermediate transfer medium (1) preparedabove. Then, the receiving layer of the intermediate transfer medium (1)on which the thermal transfer image was formed and the peel-off layer ofthe thermal transfer sheet according to each of the examples andcomparative examples prepared above were superposed on each other tocontact each other. Using the printer shown below, each of the voltagesshown in Table 2 below was applied to the back surface side of thethermal transfer sheet to remove a predetermined region of the transferlayer composed of a layered structure of the release layer, theprotective layer, and the receiving layer from the intermediate transfermedium (1). At this time, the removal state of the transfer layer wasvisually examined, and the peel-off property was evaluated based on theevaluation criteria shown below. A similar evaluation was also performedon the intermediate transfer medium (2). The evaluation results areshown in Table 2. The cases where the peel-off property was evaluated asgood for both of the intermediate transfer media (1) and (2) at anapplied voltage 21 (V) were used as the examples.

(Printer)

Thermal head: KEE-57-12GAN2-STA (KYOCERA Corporation)

Average resistance of the heating element: 3303 (Ω)

Print density in the horizontal scanning direction: 300 (dpi)

Print density in the vertical scanning direction: 300 (dpi)

Line period: 2 (msec/line)

Print start temperature: 35 (° C.)

Pulse Duty ratio: 85(%)

Applied voltage: 18 (V) to 27 (V)

“Evaluation Criteria”

-   -   A: The transfer layer corresponding to the “predetermined        region” was accurately removed.    -   B: The transfer layer was removed in such a manner that a        portion of the transfer layer corresponding to the        “predetermined region” slightly remained, or the transfer layer        slightly extended off the “predetermined region”; however, the        peel-off property was at a level that practically causes no        problem.    -   C: The transfer layer was removed in such a manner that a        portion of the transfer layer corresponding to the        “predetermined region” remained, or the transfer layer extended        off the “predetermined region”; however, the peel-off property        was at a level that practically causes no problem.    -   NG (1): The transfer layer corresponding to the “predetermined        region” was not accurately removed, and the peel-off property        was poor.    -   NG (2): The transfer layer corresponding to the “predetermined        region” was not removed at all, and the peel-off property was        poor.

TABLE 2 Type of Intermediate Transfer Medium Polyester Resin (1) (2) (1)(2) (1) (2) (1) (2) Mw Tg 27 (V) 24 (V) 21 (V) 18 (V) Example B-1 800085 A A A A A A B B Example B-2 6000 82 A A A A A A B B Example B-3 800063 A A A A A A B B Example B-4 7000 53 B A B A B A B B Example B-5 1700067 B A B A B A C B Example B-6 15000 65 B A B A B A C B Example B-7 300053 NG (2) NG (2) A A B A B B Example B-8 6000 82 B A B A B A B B ExampleB-9 6000 82 A A A A A A B B Example B-10 15000 101 B B B B C C NG (2) NG(1) Comparative Example B-1 None B A B A NG (1) A NG (2) B ComparativeExample B-2 6000 46 NG (2) NG (2) NG (2) NG (2) NG (2) NG (2) B BComparative Example B-3 18000 71 B B B B NG (2) NG (2) NG (2) NG (2)Comparative Example B-4 1800 40 NG (2) NG (2) NG (2) NG (2) NG (2) NG(2) B B Comparative Example B-5 34000 −25 Not evaluated because ofblocking of the thermal transfer sheet Comparative Example B-6 30000 −70Not evaluated because of blocking of the thermal transfer sheet

(Preparation of thermal transfer sheet 1)

As a substrate, a 4.5-μm-thick polyethylene terephthalate film subjectedto an easy adhesion treatment in advance was used, and a peel-off layercoating liquid 31 of the composition shown below was applied onto onesurface, i.e., the easy adhesion-treated surface, of the substrate togive a thickness of 1 μm in a dried state, and dried to form a peel-offlayer. Furthermore, the back face layer coating liquid of thecomposition shown above was applied onto the other surface of thesubstrate to give a thickness of 0.8 μm in a dried state, and dried toform a back face layer. As a result, a thermal transfer sheet 1 wasobtained.

<Peel-Off Layer Coating Liquid 31>

Vinyl chloride-vinyl acetate copolymer 14 parts (Mn: 12000, Tg: 76° C.)(SOLBIN (registered trademark) CNL; Nisshin Chemical Co., Ltd.) Acrylicresin (Mw: 25000, Tg: 105° C.)  4 parts (DIANAL (registered trademark)BR87; Mitsubishi Rayon Co., Ltd.) Polyester resin  2 parts (UE-9885;Unitika Ltd.) Methyl ethyl ketone 80 parts

(Preparation of Thermal Transfer Sheet 2)

A thermal transfer sheet 2 was obtained using the same preparationmethod as that for the thermal transfer sheet 1, except that thepeel-off layer coating liquid 31 was replaced with a peel-off layercoating liquid 32 of the composition shown below to form a peel-offlayer.

<Peel-Off Layer Coating Liquid 32>

Vinyl chloride-vinyl acetate copolymer 14 parts (Mn: 12000, Tg: 76° C.)(SOLBIN (registered trademark) CNL; Nisshin Chemical Co., Ltd.) Acrylicresin (Mw: 25000, Tg: 105° C.)  6 parts (DIANAL (registered trademark)BR87; Mitsubishi Rayon Co., Ltd.) Methyl ethyl ketone 80 parts

(Preparation of Thermal Transfer Sheet 3)

A thermal transfer sheet 3 was obtained using the same preparationmethod as that for the thermal transfer sheet 1, except that thepeel-off layer coating liquid 31 was replaced with a peel-off layercoating liquid 33 of the composition shown below to form a peel-offlayer.

<Peel-Off Layer Coating Liquid 33>

Polyester resin (Tg: 82° C., Mn: 6000) 20 parts (UE-9885; Unitika Ltd.)Methyl ethyl ketone 80 parts

(Preparation of Thermal Transfer Sheet 4)

A thermal transfer sheet 4 was obtained using the same preparationmethod as that for the thermal transfer sheet 1, except that thepeel-off layer coating liquid 31 was replaced with a peel-off layercoating liquid 34 of the composition shown below to form a peel-offlayer.

<Peel-Off Layer Coating Liquid 34>

Polyester resin (Tg: 67° C., Mn: 17000) 20 parts (Vylon (registeredtrademark) 200; Toyobo Co., Ltd.) Methyl ethyl ketone 80 parts

(Preparation of Thermal Transfer Sheet 5)

A thermal transfer sheet 5 was obtained using the same preparationmethod as that for the thermal transfer sheet 1, except that thepeel-off layer coating liquid 31 was replaced with a peel-off layercoating liquid 35 of the composition shown below to form a peel-offlayer.

<Peel-Off Layer Coating Liquid 35>

Polyester resin (Tg: 101° C., Mn: 15000) 20 parts (UE-9900; UnitikaLtd.) Methyl ethyl ketone 80 parts

(Preparation of Thermal Transfer Sheet 6)

A thermal transfer sheet 6 was obtained using the same preparationmethod as that for the thermal transfer sheet 1, except that thepeel-off layer coating liquid 31 was replaced with a peel-off layercoating liquid 36 of the composition shown below to form a peel-offlayer.

<Peel-Off Layer Coating Liquid 36>

Polyurethane resin (Tg: 92° C., Mn: 16000) 20 parts (UE-1700; ToyoboCo., Ltd.) Methyl ethyl ketone 80 parts

(Preparation of Thermal Transfer Sheet 7)

A thermal transfer sheet 7 was obtained using the same preparationmethod as that for the thermal transfer sheet 1, except that thepeel-off layer coating liquid 31 was replaced with a peel-off layercoating liquid 37 of the composition shown below to form a peel-offlayer.

<Peel-Off Layer Coating Liquid 37>

Polyurethane resin (Tg: 56° C., Mn: 10000) 20 parts (UE-4410; ToyoboCo., Ltd.) Methyl ethyl ketone 80 parts

(Preparation of Thermal Transfer Sheet A)

A thermal transfer sheet A was obtained using the same preparationmethod as that for the thermal transfer sheet 1, except that thepeel-off layer coating liquid 31 was replaced with a peel-off layercoating liquid 0 of the composition shown below to form a peel-offlayer.

<Peel-Off Layer Coating Liquid O>

Vinyl chloride-vinyl acetate copolymer  9 parts (Mn: 12000, Tg: 76° C.)(SOLBIN (registered trademark) CNL; Nisshin Chemical Co., Ltd.) Acrylicresin (Mw: 25000, Tg: 105° C.) 11 parts (DIANAL (registered trademark)BR87; Mitsubishi Rayon Co., Ltd.) Methyl ethyl ketone 80 parts

(Preparation of Thermal Transfer Sheet B)

A thermal transfer sheet B was obtained using the same preparationmethod as that for the thermal transfer sheet 1, except that thepeel-off layer coating liquid 31 was replaced with a peel-off layercoating liquid P of the composition shown below to form a peel-offlayer.

<Peel-Off Layer Coating Liquid P>

Acrylic resin (Mw: 25000, Tg: 105° C.) 20 parts (DIANAL (registeredtrademark) BR87; Mitsubishi Rayon Co., Ltd.) Methyl ethyl ketone 80parts

(Combination of Transfer Foil and Thermal Transfer Sheet)

The thermal transfer sheets prepared above and the intermediate transfermedia (1) and (2) prepared above as transfer foils were combined asshown in Table 3 below, to make combinations according to examples andcomparative examples. The combinations of transfer foils and thermaltransfer sheets in which the adhesion between the transfer layer and thepeel-off layer under the “specific measurement conditions” was not lessthan 0.03 N/cm were used as the combinations of the examples, and thecombinations of transfer foils and thermal transfer sheets in which theadhesion between the transfer layer and the peel-off layer under the“specific measurement conditions” was less than 0.03 N/cm were used asthe combinations of the comparative examples.

(Measurement of Adhesion)

A photo-like thermal transfer image was formed by sublimation transferon the receiving layer of the intermediate transfer medium as a transferfoil in each of the combinations shown in Table 3 below. Then, thereceiving layer of the intermediate transfer medium on which the thermaltransfer image was formed and the peel-off layer of the thermal transfersheet in each of the combinations shown in Table 3 were superposed oneach other to contact each other. Using the test printer shown below,the transport speed for the thermal transfer sheet was set to 42.3mm/sec, and each of the energies shown in Table 3 below was applied tothe back surface side of the thermal transfer sheet to remove apredetermined region of the transfer layer composed of a layeredstructure of the release layer, the protective layer, and the receivinglayer from the intermediate transfer medium. At the time of removal ofthe predetermined region of the transfer layer from the intermediatetransfer medium, the tensile strength of the peel-off layer upon peelingoff the transfer layer of the intermediate transfer medium adhered tothe peel-off layer, from the support along with the peel-off layer, wasmeasured with a tension meter (model: ASK-1000; Ohkura Industry Co.,Ltd.) provided between the take-up roll for the thermal transfer sheetand the heating device (thermal head) in the printer. This tensilestrength was determined as the adhesion between the transfer layer andthe peel-off layer. Table 3 shows the measurement results of adhesion.The adhesion (N/cm) is the value obtained by dividing the value measuredwith the tension meter by the width of the energy-applied region. Thepeel angle of the transfer layer at the time of peeling off the transferlayer from the support was 50° C.

(Test Printer)

Average resistance of the heating element: 5241 (Ω)

Print density in the horizontal scanning direction: 300 (dpi)

Print density in the vertical scanning direction: 300 (dpi)

Line period: 2 (msec/line)

Print start temperature: 29.0 to 36.0 (° C.)

Pulse Duty ratio: 85(%)

Applied voltage: 18 (V) to 24 (V)

Transport speed: 42.3 mm/sec

Width of the energy-applied region: 4.1846 (cm)

(Evaluation of Peel-Off Property (3))

In the measurement of adhesion described above, the removal state of thetransfer layer removed by the peel-off layer was visually examined, andthe peel-off property was evaluated based on the evaluation criteriashown below. The evaluation results are also shown in Table 3.

“Evaluation Criteria”

-   -   A: The transfer layer corresponding to the “predetermined        region” was accurately removed.    -   B: The transfer layer was removed in such a manner that a        portion of the transfer layer corresponding to the        “predetermined region” slightly remained, or the transfer layer        slightly extended off the “predetermined region”; however, the        peel-off property was at a level that practically causes no        problem.    -   C: The transfer layer was removed in such a manner that a        portion of the transfer layer corresponding to the        “predetermined region” remained, or the transfer layer extended        off the “predetermined region”; however, the peel-off property        was at a level that practically causes no problem.    -   NG (1): The transfer layer corresponding to the “predetermined        region” was not accurately removed, and the peel-off property        was poor.    -   NG (2): The transfer layer corresponding to the “predetermined        region” was not removed at all, and the peel-off property was        poor.

TABLE 3 Applied Energy Thermal Intermediate 0.105 (mJ/dot) 0.143(mJ/dot) 0.187 (mJ/dot) Transfer Transfer Peel-Off Peel-Off Peel-OffSheet Medium Peel Force Property Peel Force Property Peel Force PropertyExample 1 1 1 0.290 B 0.341 A 0.412 A Example 2 2 1 0.263 B 0.373 B0.430 A Example 3 3 1 0.286 B 0.322 A 0.500 B Example 4 4 1 0.316 B0.340 B 0.436 B Example 5 1 2 0.268 B 0.271 A 0.388 A Example 6 2 20.319 B 0.294 A 0.364 A Example 7 3 2 0.271 B 0.352 A 0.477 B Example 84 2 0.293 B 0.330 A 0.406 A Example 9 5 2 0.077 C 0.126 C 0.290 BExample 10 6 2 0.149 C 0.173 C 0.298 B Example 11 7 2 0.284 B 0.266 B0.380 B Comparative Example 1 A 1 0.021 NG (1) 0.021 NG (1) 0.024 NG (1)Comparative Example 2 B 1 0.017 NG (2) 0.020 NG (1) 0.020 NG (1)Comparative Example 3 B 2 0.019 NG (1) 0.017 NG (1) 0.017 NG (1)

REFERENCE SIGNS LIST

-   1 Substrate-   2 Primer layer-   4 Peel-off layer-   5 Back face layer-   7 Dye layer-   8 Fusible layer-   10 Thermal transfer sheet-   16 Heating device-   30 Intermediate transfer medium (transfer foil)-   31 Transfer layer-   A Peripheral edges of transfer layer-   B Region allocated for IC chip-   200 Printer-   201 Thermal transfer sheet feed device-   202 Heating device-   203 Thermal transfer sheet take-up device-   204 Measurement device-   205 Peel device

1. A thermal transfer sheet comprising: a substrate; and a peel-off layer affixed to the substrate, wherein a surface of the substrate is subjected to an adhesive treatment, or a primer layer is provided between the substrate and the peel-off layer, wherein the peel-off layer is not removed from the substrate, and wherein the peel-off layer contains a polyester-type resin having a number average molecular weight (Mn) of not more than 17000 and having a glass transition temperature (Tg) of not less than 50° C. and not more than 120° C.
 2. The thermal transfer sheet according to claim 1, wherein the polyester-type resin has a number average molecular weight (Mn) of not less than 3500 and less than
 9000. 3. The thermal transfer sheet according to claim 1, wherein the polyester-type resin has a glass transition temperature (Tg) of not less than 50° C. and not more than 100° C.
 4. The thermal transfer sheet according to claim 2, wherein the polyester-type resin has a glass transition temperature (Tg) of not less than 50° C. and not more than 100° C. 